
import {
	Blob,
	btoa,
	createImageBitmap,
	CSSStyleDeclaration,
	performance,
	document,
	DOMParser,
	EventTarget,
	fetch,
	Headers,
	HTMLCanvasElement,
	Image,
	HTMLImageElement,
	ImageBitmap,
	location,
	navigator,
	Request,
	requestAnimationFrame,
	cancelAnimationFrame,
	Response,
	URL,
	window,
	self,
	WebAssembly,
	Worker,
	XMLHttpRequest,
	ImageData,
	TextDecoder,
	core
	} from 'dhtml-weixin';
/**
 * Sepia tone shader
 * based on glfx.js sepia shader
 * https://github.com/evanw/glfx.js
 */

const SepiaShader = {

	name: 'SepiaShader',

	uniforms: {

		'tDiffuse': { value: null },
		'amount': { value: 1.0 }

	},

	vertexShader: /* glsl */`

		varying vec2 vUv;

		void main() {

			vUv = uv;
			gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );

		}`,

	fragmentShader: /* glsl */`

		uniform float amount;

		uniform sampler2D tDiffuse;

		varying vec2 vUv;

		void main() {

			vec4 color = texture2D( tDiffuse, vUv );
			vec3 c = color.rgb;

			color.r = dot( c, vec3( 1.0 - 0.607 * amount, 0.769 * amount, 0.189 * amount ) );
			color.g = dot( c, vec3( 0.349 * amount, 1.0 - 0.314 * amount, 0.168 * amount ) );
			color.b = dot( c, vec3( 0.272 * amount, 0.534 * amount, 1.0 - 0.869 * amount ) );

			gl_FragColor = vec4( min( vec3( 1.0 ), color.rgb ), color.a );

		}`

};

export { SepiaShader };
